1. Field of the Invention
The present invention relates to a color filter and an electronic display device using the color filter.
2. Description of the Related Art
In recent years, the color filter is used as a color separation filter in a liquid crystal display, an organic EL display, an electronic paper, a viewfinder for a video camera, an imaging device such as CCD, etc., and in a color image sensor, a line sensor for color copy, etc., and development of the industrial product using various color filters is progressing. Such a color filter is being required to have high-quality color characteristics in luminance, chromaticity, contrast, etc., and high-quality characteristics such as the reduction in color unevenness and improvement of color separation performance are being demanded and a higher degree of fineness is also being demanded.
It is known that in the color filter, pixels colored with only pigments are generally excellent in heat resistance and light resistance, but are inferior to pixels colored with only dye, because the transmittance of transmitted light is affected by scattering of pigment particles.
In the pigment-based color filter, colors are adjusted in order to make an attempt to improve luminance, but there is a problem of sacrificing a color reproduction range and white balance. In this case, the use of a dye-based color filter is conceivable, but, if a cold cathode tube (CCFL) light source is used, the dye-based color filter is deteriorated, and therefore, there is such a problem that the color filter cannot be used in a liquid crystal device (LCD).
Therefore, a technique of using both dye and pigment in a color filter is being examined. For example, a color filter in which pixels colored with pigment and pixels colored with dye are being laminated is proposed (refer to Japanese Patent Application Laid-Open (JP-A) No. 05-2106). This proposal compensates for the disadvantage of pixels in which the dye and the pigment are used alone, but this proposal eventually halves the advantage and the disadvantage of the case where the dye and the pigment are used alone.
Furthermore, Japanese Patent Application Laid-Open (JP-A) No. 2009-527014 discloses that the color filter containing copper phthalocyanine and anthraquinone can enhance contrast.
Moreover, Japanese Patent (JP-B) No. 4156476 discloses the liquid crystal device in which the areas of red (R), green (G), and blue (B) pixels are different and which uses an LED as a light source.
JP-A Nos. 2010-44981 and 2010-171007 disclose organic EL display devices having a color filter containing a pigment or a dye.
JP-A No. 2007-41169 discloses an electronic paper display device having a color filter and enabling color display.
However, the preceding technical documents do not disclose or suggest a color filter in which at least one of the red (R) pixel, the green (G) pixel, and the blue (B) pixel includes one or more kind of dyes and one or more kind of pigments and the pixel area of each color is different from one another and it is obvious that the significant working effect that the luminance of white can be improved while keeping the same chromaticity of red (R), green (G), and blue (B) as well as the chromaticity of white as before cannot be obtained even by combining the preceding technical documents.
Therefore, in the present circumstances, a technique is being demanded, which can provide a color filer capable of improving the luminance of white while keeping the same chromaticity of red (R), green (G), and blue (B) and the chromaticity of white as before, and an electronic display device using the color filter.